D.L. Ledferd did some work on this amp. This is what I found in the Vintage Amp Bulletin Forum. It's from a posting by 'Naked Clarke' who states: [quote: 'Old D.L Ledferd wired up a lot of Fender amps in the late '60s and early '70s. Many of the 400 PS amps with his stamp also say Wired By and include the actual date. He may be as famous as Lily, Lupe and others whose names are written on bits of masking tape and stuck inside Fender tweed amps.end of quote]. It's from a thread about a 1969 Bassman restauration.